The present invention relates to disposable blood chambers and more particularly to disposable blood chambers suitable for use in the colormetric determination of hemoglobin and billirubin.
Photometric instruments are used for colorimetry of various liquids, including blood samples. Such instruments of specialized use with blood samples include hemoglobinometers and billirubinometers. An example of a hemoglobinometer in which the present invention may be used is described in U.S. Pat. No. 2,482,650, issued on Sept. 20, 1949 to Morden G. Brown and Harry F. Lundberg. The details of this instrument will not be further described herein except insofar as necessary to an understanding of this invention.
In the Brown and Lundberg patent, the liquid (blood) sample is introduced into the photometer by a sample chamber of three parts, best shown in FIGS. 8 and 9 of the patent. These parts include a lower glass plate defining certain channels, an an upper glass plate which fits on the lower plate to define therewith a capillary chamber of precise thickness. The two plates are held together by a spring clip having a handle by which the plates are inserted into, and removed from, the instrument. The capillary chamber holds the blood sample for photometric analysis. The glass plates are retained and washed between successive use. Their use involves the manipulating of three separate parts in addition to the blood sample itself.
U.S. Pat. No. 3,565,537 discloses a two piece chamber construction where the pieces are joined by ultrasonic welding.
U.S. Pat. No. 3,705,000 discloses a one piece chamber having a well for temporarily holding a blood sample.
Neither the welded two piece construction or unitary one piece chamber has been acceptable because of the requirement for exceptionally close tolerances in the capillary chamber which cannot be consistently achieved on a commercial scale. The three piece construction having glass chamber halves has been well accepted, but its high cost requires that it be reused. Increasing labor costs and the possibility of cross-contamination have increased the demand for a disposable chamber.
It is an object of the present invention to provide a disposable blood chamber.
It is another object of the present invention to provide an imexpensive disposable blood chamber without sacrificing accurate chamber dimensions.
It is still another object of the present invention to provide a blood chamber that cannot be disassembled for sterilization and reuse.